title: Discriminative stimulus effects of etorphine in Rhesus monkeys.
abstract: Two rhesus monkeys were trained to discriminate the IM injection of etorphine (0.001 mg/kg) from saline in a task in which 20 consecutive responses on one of two levers resulted in food delivery. In both monkeys, etorphine (0.0001--0.0018), meperidine (0.1--1.0 mg/kg), morphine (0.1--3.2 mg/kg), and codeine (0.3--3.2) produced dose-related increases in the percentage of total session responses that occurred on the etorphine-appropriate lever. In contrast, ethylketazocine, SKF-10047, and pentazocine, at doses up to and including those that suppressed response rates, produced responses primarily on the saline-appropriate lever. Thus, etorphine-like narcotics, including morphine, have discriminative stimulus effects in rhesus monkeys which can be distinguished from those produced by narcotics with nonmorphine-like actions such as ethylketazocine, SKF-10047, and pentazocine.
mesh_terms: D000818:Animals; D003061:Codeine / Q000494:pharmacology; D003496:Cyclazocine / Q000031:analogs & derivatives / Q000494:pharmacology; D004193:Discrimination Learning / Q000187:drug effects*; D016314:Ethylketocyclazocine; D005048:Etorphine / Q000494:pharmacology*; D008253:Macaca mulatta; D008297:Male; D008614:Meperidine / Q000494:pharmacology; D009019:Morphinans / Q000494:pharmacology*; D009020:Morphine / Q000494:pharmacology; D010423:Pentazocine / Q000494:pharmacology; D010620:Phenazocine / Q000031:analogs & derivatives / Q000494:pharmacology; D012965:Sodium Chloride
chemical_list: D009019:Morphinans; D005048:Etorphine; D012965:Sodium Chloride; D016314:Ethylketocyclazocine; C012134:SK&F 10047; D009020:Morphine; D008614:Meperidine; D010620:Phenazocine; D003496:Cyclazocine; D010423:Pentazocine; D003061:Codeine